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<H1>STD -- Set Direction Flag</H1>

<PRE>
Opcode  Instruction   Clocks    Description

FD      STD           2         Set direction flag so (E)SI and/or (E)DI
                                decrement
</PRE>


<H2>Operation</H2>

<PRE>
DF := 1;
</PRE>

<H2>Description</H2>

STD sets the direction flag to 1, causing all subsequent string operations
to decrement the index registers, (E)SI and/or (E)DI, on which they
operate.

<H2>Flags Affected</H2>

DF := 1

<H2>Protected Mode Exceptions</H2>

None

<H2>Real Address Mode Exceptions</H2>

None

<H2>Virtual 8086 Mode Exceptions</H2>

None


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